太湖不同生态型湖区悬浮颗粒磷空间分布和降解速率

The spatial distribution and degradation characteristic of phosphorus in suspended particulate matter among different ecological types in Taihu

对太湖不同生态型湖区水体悬浮颗粒物含量,有机磷组成及降解特征进行分析,研究了富营养化湖泊颗粒磷性质及其对水体磷循环的影响.太湖颗粒P平均占水体TP浓度的75.86%;不同生态类型湖区间颗粒物性质差异明显,河口区和湖心区的颗粒物含量高于藻型湖区和草型湖区,但颗粒物有机质比例分布却相反.利用31P液相核磁共振法(31P-NMR)发现太湖悬浮颗粒P的成分包括膦酸酯,正磷酸盐,磷酸单酯,磷酸二酯,焦磷酸盐和多聚磷酸盐6类,含量分别为1.06%,50.99%,33.02%,2.48%,10.68%和3.80%.不同生态型湖区之间颗粒P组成差异明显,河口区正磷酸盐含量最高,达到82.57%,藻型湖区和湖心区颗粒有机磷比例最高,分别达到达到64.02%和63.95%;颗粒物焦磷酸盐和多聚磷酸盐可能以藻源性颗粒物来源为分别与Chla浓度呈显著相关(P<0.05;P<0.01).颗粒态生物可利用性磷(PEHP)与正磷酸盐显著相关(P<0.05),说明颗粒物正磷酸盐是颗粒物生物可利用性磷的重要来源.太湖PEHP降解速率平均为47.3min,PEHP占水体生物可利用磷(EHP)的65.16%,说明颗粒P是水体溶解性反应磷(SRP)补充的重要来源.

The contents of particulate matter, composition of organic phosphorus and the degradation characteristics of the water particulates in different ecological types in Lake Taihu were analyzed. The properties of particulate phosphorus and their impact on the water phosphorus cycle of eutrophic lake were researched. The particulate P is 75.86% of TP concentration,in Taihu. and the differences were obvious. Particulate matter content of the estuary zone and the central zone was higher than that of the algae type zone and the grass type zone, but particulate organic matter ratio of the latter two was higher than that of the formers.The P species composition of water particulate in different lake area by using 31P nuclear magnetic resonance method（31P-NMR） showed that the composition of particulate organic phosphorus includes 6kinds, including phosphonates, orthophosphate, orthophosphate monoesters, orthophosphate diester, pyrophosphate and polyphosphate. The content was respectively 1.06%, 50.99%, 33.02%, 2.48%, 10.68% and 3.80%. 31P-NMR results show that the distribution of particulate phosphorus between different ecological types is obvious. The content of orthophosphate in the estuary zone was 82.57%, the highest. The algae type zone and the central zone were with higher Chla concentration and the highest particle organic phosphorus ratio meanwhile, respectively reached 64.02% and 63.95%, indicating that different types of ecological system had significant impacts on particulate phosphorus group. The concentration of pyrophosphate and polyphosphate was significantly correlated with the concentration of Chla （P〈0.05; P〈0.01）. Particulate enzymatically hydrolysable phosphorus （PEHP） was significantly correlated to the orthophosphate （P〈0.05）, which indicated that the particles was the important sources of biogentic phosphorus in Taihu. The mean degradation time of PEHP in Taihu was 47.23min, which was 65.16% of enzymatically hydrolysable phosphorus （EHP）, indicating that particulate Pis an important source of soluble reactive P（SRP）.